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A {gamma}-ray linear polarization measurement has been performed to directly determine the parities for the levels in 146Gd nucleus. High-spin states in this nucleus were populated in a reaction 115In + 34S at 140 MeV incident energy. Linearly polari zed {gamma} - rays emitted from oriented states were measured using a Compton polarimeter consisting of an array of 8 Compton-suppressed Clover detectors. Unambiguous assignments of the spin and parity have been made for most of the observed levels and changes made in the previously reported spin-parity assignments for a few levels. Shell model calculations performed with judicious truncation over the {pi}(gdsh) valence space interpret the structure of only the low-lying levels up to J{pi} = 19+ and 9-. N = 82 neutron-core breaking is found to be essential for high spin states with excitation energies Ex > 7 MeV.
We report the first observation of high-spin states in nuclei in the vicinity of the island of inversion, populated via the 18O+18O fusion reaction at an incident beam energy of 34 MeV. The fusion reaction mechanism circumvents the limitations of non -equilibrated reactions used to populate these nuclei. Detailed spin-parity measurements in these difficult to populate nuclei have been possible from the observed coincidence anisotropy and the linear polarization measurements. The spectroscopy of 33,34P and 33S is presented in detail along with the results of calculations within the shell model framework.
High spin states in $^{103}$Ag were investigated with the Gammasphere array, using the $^{72}$Ge($^{35}$Cl,$2p2n$)$^{103}$Ag reaction at an incident beam energy of 135 MeV. A $Delta J$=1 sequence with predominantly magnetic transitions and two nearly -degenerate $Delta J=1$ doublet bands have been observed. The dipole band shows a decreasing trend in the $B(M1)$ strength as function of spin, a well established feature of magnetic bands. The nearly-degenerate band structures satisfy the three experimental signatures of chirality in the nuclei; however microscopic calculations are indicative of a magnetic phenomenon
Excited states of the neutron deficient $^{103}$Cd nucleus have been investigated via the $^{72}$Ge($^{35}$Cl, p3n) reaction at beam energy of 135 MeV by use of in-beam spectroscopic methods. Gamma rays depopulating the excited states were detected u sing the Gammasphere spectrometer with high-fold $gamma$-ray coincidences. A quadrupole $gamma$-ray coincidence analysis ($gamma^{4}$) has been used to extend the known level scheme. The positive parity levels have been established up to $J = 35/2hbar$ and $E_{x} = 7.071$ MeV. In addition to the observation of highly-fragmented level scheme belonging to the positive-parity sequences at E$_{x}sim$ 5 MeV, the termination of a negative-parity sequence connected by $E2$ transitions has been established at $J = 47/2 hbar$ and $E_{x} = 11.877$ MeV. The experimental results corresponding to both the positive- and negative-parity sequences have been theoretically interpreted in the framework of the core particle coupling model. Evidence is presented for a shape change from collective prolate to non-collective oblate above the $J^{pi} = 39/2^{-}$ (8011 keV) level and for a smooth termination of the negative-parity band.
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